Electronic component device

ABSTRACT

An electronic component having thermal shock resistance and high reliability includes an element having a functional part and a first frame-shaped electrode surrounding the functional part, a substrate including a second frame-shaped electrode, and a solder sealing frame provided on the surface of at least one of the first frame-shaped electrode and the second frame-shaped electrode. In the electronic component device, the element and the substrate are bonded with the solder sealing frame, and the functional part provided on the element is hermetically sealed in a space formed between the element and the substrate. When the difference in expansion in the x direction between the element and the substrate is represented by Q x  and the difference in expansion in the y direction between the element and the substrate is represented by Q y , then in each of the first frame-shaped electrode, the second frame-shaped electrode, and the solder sealing frame, a width of a strip-shaped portion extending in the direction having the larger difference in expansion is smaller than a width of a strip-shaped portion extending in the direction having the smaller difference in expansion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic component device in whicha rectangular plate-shaped electronic component element having afunctional part thereon is mounted on a substrate with bumps. In furtherdetail, the present invention relates to an electronic component devicein which a rectangular plate-shaped electronic component element ismounted on a substrate so that a functional part of the electroniccomponent element is hermetically sealed. The electronic componentelement has a coefficient of linear expansion in the x direction along aside of the rectangle and a coefficient of linear expansion in the ydirection orthogonal to the x direction in the plane of the rectangle,wherein the coefficients of linear expansion being different from eachother.

2. Description of the Related Art

Hitherto, various electronic component devices in which an electroniccomponent element (hereinafter also abbreviated to as an element), suchas a SAW element or a high-frequency element, is installed on asubstrate have been proposed.

For example, Japanese Unexamined Patent Application Publication No.4-293310 discloses a surface acoustic wave device in which a SAW elementis mounted on a base plate with bumps. In more detail, hot-side landsare provided on a surface of the base plate and solder bumps areprovided on the corresponding hot-side lands. In addition, aframe-shaped earth-side land is provided on the surface of the baseplate so as to surround the hot-side lands. A solder sealing frame isprovided on the frame-shaped earth-side land. On the other hand,interdigital transducers (IDT), hot-side patterns, and earth-sidepatterns are provided on a surface of a SAW element chip to form afunctional part. The SAW element is fixed on the base plate with apredetermined space therebetween such that the surface having the IDTsof the SAW element faces the surface of the base plate. The space ishermetically sealed with the solder sealing frame.

However, in the surface acoustic wave device described in JapaneseUnexamined Patent Application Publication No. 4-293310, the coefficientof linear expansion in the x direction along a side of the rectangularplate-shaped SAW element is different from the coefficient of linearexpansion in the x direction of the base plate. In addition, thecoefficient of linear expansion in the y direction, which lies in theplane of the rectangle of the SAW element and is orthogonal to the xdirection, is different from the coefficient of linear expansion in they direction of the base plate. Thus, in the SAW element and the baseplate, the coefficients of linear expansion in the same direction aredifferent from each other. Therefore, when a thermal shock is appliedduring a reliability test or during use, a large difference in expansionis generated between the SAW element and the base plate. Consequently, astrain or a fatigue breaking is generated in the sealed portion,resulting in a sealing failure. This causes a problem that the lifetimefor thermal shock resistance required for general electronic componentdevices cannot be satisfied.

SUMMARY OF THE INVENTION

In order to overcome the problems described above, preferred embodimentsof the present invention provide an electronic component devicesatisfying the lifetime for thermal shock resistance required forgeneral electronic component devices and having excellent reliability.

The preferred embodiments provide an electronic component deviceincluding a rectangular plate-shaped element including a front face, areverse face, a functional part provided on the front face, and a firstframe-shaped electrode surrounding the functional part, wherein thecoefficient of linear expansion in the x direction along a side of therectangle is different from the coefficient of linear expansion in the ydirection orthogonal to the x direction in the rectangular plane; asubstrate including a front face, a reverse face, and a secondframe-shaped electrode provided on the front face at a positioncorresponding to the first frame-shaped electrode; and a solder sealingframe provided on the surface of at least one of the first frame-shapedelectrode and the second frame-shaped electrode. In the electroniccomponent device, each of the first frame-shaped electrode, the secondframe-shaped electrode, and the solder sealing frame includes astrip-shaped portion extending in the x direction and a strip-shapedportion extending in the y direction, the element and the substrate arebonded with the solder sealing frame, and the functional part providedon the front face of the element is hermetically sealed in a spaceformed between the element and the substrate. In the electroniccomponent device, the difference in expansion in the x direction betweenthe element and the substrate is represented by Q_(x) and the differencein expansion in the y direction between the element and the substrate isrepresented by Q_(y). Then, in each of the first frame-shaped electrode,the second frame-shaped electrode, and the solder sealing frame, thewidth of the strip-shaped portion extending in the direction in whichthe larger difference in expansion is generated between the differencesQ_(x) and Q_(y) in expansion is smaller than the width of thestrip-shaped portion extending in the direction in which the smallerdifference in expansion is generated between the differences Q_(x) andQ_(y) in expansion.

According to another preferred embodiment of the present invention, thethickness of the solder sealing frame is about 18 μm or more.

According to another preferred embodiment of the present invention, thecoefficient of linear expansion in the x direction of the substrate isrepresented by A_(x) and the coefficient of linear expansion in the ydirection of the substrate is represented by A_(y). The coefficient oflinear expansion in the x direction of the element is represented byB_(x) and the coefficient of linear expansion in the y direction of theelement is represented by B_(y). The length of the external side of thestrip-shaped portion extending in the x direction of the first andsecond frame-shaped electrodes is represented by dl_(x) and the lengthof the external side of the strip-shaped portion extending in the ydirection of the first and second frame-shaped electrodes is representedby dl_(y). Then, the difference Q_(x) in expansion is represented byQ_(x)=|A_(x)−B_(x)|×dl_(x) (mm/° C.), and the difference Q_(y) inexpansion is represented by Q_(y)=|A_(y)−B_(y)|×dl_(y) (mm/° C.), thelarger difference in expansion between the differences Q_(x) and Q_(y)in expansion is about 2.2×10⁻⁵ (mm/° C.) or less.

According to another preferred embodiment of the present invention, whenthe ratio of flexural rigidity in the x direction between the elementand the substrate is represented by R_(x) and the ratio of flexuralrigidity in the y direction between the element and the substrate isrepresented by R_(y), the larger ratio of flexural rigidity between theratios R_(x) and R_(y) of flexural rigidity is about 1.2 or less.

According to another preferred embodiment of the present invention, theelement is a surface acoustic wave element.

In the electronic component device according to another preferredembodiment of the present invention, the difference in expansion in thex direction between the element and the substrate is represented byQ_(x) and the difference in expansion in the y direction between theelement and the substrate is represented by Q_(y). Then, in each of thefirst frame-shaped electrode, the second frame-shaped electrode, and thesolder sealing frame, the width of the strip-shaped portion extending inthe direction in which the larger difference in expansion is generatedbetween the differences Q_(x) and Q_(y) in expansion is smaller than thewidth of the strip-shaped portion extending in the direction in whichthe smaller difference in expansion is generated between the differencesQ_(x) and Q_(y) in expansion. Therefore, the lifetime for thermal shockresistance can be improved, and thus the lifetime for thermal shockresistance required for general electronic component devices can besatisfied.

In the electronic component device according to another preferredembodiment of the present invention, when the thickness of the soldersealing frame is about 18 μm or more, the lifetime for thermal shockresistance of the electronic component device can be further improved.

In the electronic component device according to another preferredembodiment of the present invention, when the larger difference inexpansion between the differences Q_(x) and Q_(y) in expansion is about2.2×10⁻⁵ (mm/° C.) or less, the lifetime for thermal shock resistance ofthe electronic component device can be further improved.

In the electronic component device according to another preferredembodiment of the present invention, when the larger ratio of flexuralrigidity between the ratios R_(x) and R_(y) of flexural rigidity isabout 1.2 or less, the lifetime for thermal shock resistance of theelectronic component device can be further improved.

Other features, elements, steps, advantages and characteristics of thepresent invention will become more apparent from the following detaileddescription of preferred embodiments thereof with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an electronic component device accordingto a preferred embodiment of the present invention.

FIGS. 2A and 2B are an exploded perspective view of the electroniccomponent device shown in FIG. 1.

FIG. 3A is a plan view of a package substrate used in the electroniccomponent device in FIG. 1 and FIG. 3B is a cross-sectional view takenalong face A-A in FIG. 3A.

FIG. 4A is a plan view of an element used in the electronic componentdevice in FIG. 1 and FIG. 4B is a cross-sectional view taken along faceB-B in FIG. 4A.

FIG. 5A is a plan view of a solder sealing frame used in the electroniccomponent device in FIG. 1 and FIG. 5B is a cross-sectional view takenalong face C-C in FIG. 5A.

FIG. 6 is a graph showing the relationship between the thickness of asolder sealing frame and the maximum amplitude of equivalent strain.

FIG. 7 is a graph showing the relationship between the difference inexpansion and the maximum amplitude of equivalent strain.

FIG. 8 is a graph showing the relationship between the ratio of flexuralrigidity and the maximum amplitude of equivalent strain.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

As described above, when a thermal shock is applied to the knownelectronic component device during a reliability test or during use, astrain or a fatigue breaking is generated in the sealed portion,resulting in a problem of sealing failure. For example, in order tocheck if the lifetime for thermal shock resistance ((high temperatureside 85° C., low temperature side −55° C., 30 minutes each/1 cycle)×500cycles) required for general electronic component devices is satisfied,a thermal shock resistance test was performed (under the same conditionas that in the lifetime for thermal shock resistance) using the knownelectronic component device. As a result, the sealed portion was brokenbecause of a large difference in expansion, resulting in the sealingfailure. Thus, the lifetime for thermal shock resistance could not besatisfied.

To evaluate the lifetime for thermal shock resistance, for example, ashock is forcibly applied so that a strain is generated at a joinedportion by a solder ball. In this case, the empirical equation of “theCoffin-Manson's law” derived for the resultant strain and the lifetimefor thermal shock resistance is represented as follows: (maximumamplitude of equivalent strain)=0.325×(lifetime (cycle))^(−0.429) (referto “Kairo jisso gakkaishi” (The Journal of Japan Institute forInterconnecting and Packaging Electronic Circuits), Vol. 12, No. 6(1997), pp. 413-417, FIG. 7).

The maximum amplitude of equivalent strain in this empirical equationmeans the dimension of amplitude caused by expansion and contraction ofsolder during the thermal shock resistance test of an electroniccomponent device. Accordingly, it is known that reducing the maximumamplitude of equivalent strain can improve the lifetime for thermalshock resistance of the electronic component device.

The above empirical equation is an equation relating to the fatigue life(lifetime for thermal shock resistance) for solder bumps. However, sincethe strain generated in solder is a parameter with generality, thisequation can be applied to the lifetime for thermal shock resistance ofa sealing frame or the like.

The maximum amplitude of equivalent strain when a thermal shock wasapplied corresponding to the condition for the lifetime for thermalshock resistance required for general electronic component devices wascalculated as about 2.2% by an FEM simulation. In other words, when themaximum amplitude of equivalent strain can be decreased to about 2.2% orless, the lifetime for thermal shock resistance required for generalelectronic component devices can be satisfied.

FIG. 6 is a graph showing the relationship between the thickness ofsolder and the maximum amplitude of equivalent strain. As shown in FIG.6, in order to control the maximum amplitude of equivalent strain toabout 2.2% or less, the thickness of the solder should be about 18 μm ormore.

FIG. 7 is a graph showing the relationship between the difference inexpansion and the maximum amplitude of equivalent strain. As shown inFIG. 7, in order to control the maximum amplitude of equivalent strainto about 2.2% or less, the difference in expansion should be about2.2×10⁻⁵ mm/° C. or less.

FIG. 8 is a graph showing the relationship between the ratio of flexuralrigidity and the maximum amplitude of equivalent strain. As shown inFIG. 8, in order to control the maximum amplitude of equivalent strainto about 2.2% or less, the ratio of flexural rigidity should be about1.2 or less.

That is, the present inventor has found that, in order to control themaximum amplitude of equivalent strain to about 2.2% or less, thethickness of the solder sealing frame should be about 18 μm or more, thelarger difference in expansion between the differences Q_(x) and Q_(y)in expansion should be about 2.2×10⁻⁵ mm/° C. or less, and the largerratio of flexural rigidity between the ratios R_(x) and R_(y) offlexural rigidity should be about 1.2 or less.

Furthermore, the present inventor has found the following: In each ofthe solder sealing frame, a first frame-shaped electrode, and a secondframe-shaped electrode, when the width of a strip-shaped portionextending in the direction in which the larger difference in expansionis generated between the differences Q_(x) and Q_(y) in expansion issmaller than the width of a strip-shaped portion extending in thedirection in which the smaller difference in expansion is generatedbetween the differences Q_(x) and Q_(y) in expansion, the lifetime forthermal shock resistance of the electronic component device can beimproved.

Herein, each of the differences Q_(x) and Q_(y) in expansion means thedifferences between the coefficient of expansion of a substrate and thecoefficient of expansion of an element. The difference Q_(x) inexpansion in the x direction between the element and the substrate andthe difference Q_(y) in expansion in the y direction between the elementand the substrate are represented by equations ofQ_(x)=|A_(x)−B_(x)|×dl_(x) (mm/° C.) and Q_(y)=|A_(y)−B_(y)|×dl_(y)(mm/° C.), respectively, wherein A_(x) represents the coefficient oflinear expansion in the x direction of the substrate, A_(y) representsthe coefficient of linear expansion in the y direction of the substrate,B_(x) represents the coefficient of linear expansion in the x directionof the element, B_(y) represents the coefficient of linear expansion inthe y direction of the element, dl_(x) represents the length of theexternal side of the strip-shaped portion extending in the x directionof the first frame-shaped electrode and the second frame-shapedelectrode, and dl_(y) represents the length of the external side of thestrip-shaped portion extending in the y direction thereof.

Herein, each of the ratios R_(x) and R_(y) of flexural rigidity meansthe ratio of flexural rigidity of a substrate and the flexural rigidityof an element. The ratio R_(x) of flexural rigidity in the x directionbetween the substrate and the element and the ratio R_(y) of flexuralrigidity in the y direction between the substrate and the element arerepresented by equations of R_(x)=(at³·a_(x)·Ea)/(bt³·b_(x)·Eb) andR_(y)=(at³·a_(y)·Ea)/(bt³·b_(y)·Eb), respectively, wherein at representsthe thickness of the substrate, a_(x) represents the length of a sideextending in the x direction of the substrate, a_(y) represents thelength of a side extending in the y direction of the substrate, Earepresents the Young's modulus of the substrate, bt represents thethickness of the element, b_(x) represents the length of a sideextending in the x direction of the element, b_(y) represents the lengthof a side extending in the y direction of the element, and Eb representsthe Young's modulus of the element.

Specific, non-limiting preferred embodiments of the present inventionwill now be described with reference to the drawings, thereby clarifyingthe present invention.

FIG. 1 is a perspective view of an electronic component device 20according to a preferred embodiment of the present invention and FIGS.2A and 2B are an exploded perspective view of the electronic componentdevice 20. In the electronic component device 20, an element 10 ismounted face-down on a package substrate 1.

FIG. 3A is a plan view of a package substrate used in the electroniccomponent device 20 and FIG. 3B is a cross-sectional view taken along aface including line A-A in FIG. 3A. The package substrate 1 is anairtight flat plate component made of a glass epoxy resin. The lengtha_(x) of a side extending in the x direction of the package substrate 1is 2.0 mm, the length a_(y) of a side extending in the y direction is2.0 mm, the thickness at is 0.25 mm, and the Young's modulus Ea is340,000 MPa. Both the coefficient A_(x) of linear expansion in the xdirection of the package substrate 1 and the coefficient A_(y) of linearexpansion in the y direction thereof are 7 ppm/° C.

As shown in FIG. 3A, four rectangular plate-shaped bonding electrodes 2and a frame-shaped electrode 3 serving as a second frame-shapedelectrode (the frame-shaped electrode 14, described below, serves as thefirst frame-shaped electrode) are provided on the surface of the packagesubstrate 1. The second frame-shaped electrode 3 is disposed so as tosurround the bonding electrodes 2. The bonding electrodes 2 areconnected to outer electrodes (not shown in the figure) for surfacemounting, the outer electrodes being provided on the reverse face, viaconnecting portions in which an electrode material is embedded inthrough-holes (not shown in the figure). The frame-shaped electrode 3 isconnected to an earth-side electrode (not shown in the figure).

The frame-shaped electrode 3 has a rectangular frame shape and includesstrip-shaped portions extending in the x direction and strip-shapedportions extending in the y direction. The length al_(x) of the externalside of each strip-shaped portion extending in the x direction of theframe-shaped electrode 3 is 2.0 mm, the length al_(y) of the externalside of each strip-shaped portion extending in the y direction is 2.0mm, the width aw_(x) of the strip-shaped portion extending in the xdirection is 0.18 mm, the width aw_(y) of the strip-shaped portionextending in the y direction is 0.20 mm, and the thickness aet is 0.01mm.

FIG. 5A is a plan view of a solder sealing frame 4 used in theelectronic component device 20 and FIG. 5B is a cross-sectional viewtaken along a face including line C-C in FIG. 5A. The solder sealingframe 4 has a rectangular frame shape and includes strip-shaped portionsextending in the x direction and strip-shaped portions extending in they direction. The length cl_(x) of the external side of each strip-shapedportion extending in the x direction of the solder sealing frame 4 is2.0 mm, the length cl_(y) of the external side of each strip-shapedportion extending in the y direction is 2.0 mm, the width cw_(x) of thestrip-shaped portion extending in the x direction is 0.18 mm, the widthcw_(y) of the strip-shaped portion extending in the y direction is 0.20mm, and the thickness ct is 0.02 mm. The solder sealing frame 4 isprovided on the frame-shaped electrode 3 of the package substrate 1. Forexample, eutectic solder paste is applied on the frame-shaped electrode3 of the package substrate 1 by printing and the eutectic solder pasteis subjected to reflow soldering. Subsequently, cleaning is performed toremove the flux residue. Thus, the solder sealing frame 4 is formed. Inaddition to the printing, the solder sealing frame 4 may be formed byprecoating such as the SJ process, plating, vacuum deposition,sputtering, or the like. Although eutectic solder is used as thematerial of the solder sealing frame 4, the material is not limited toeutectic solder as long as the material is a metal that can be melted.

FIG. 4A is a plan view of the element 10 used in the electroniccomponent device 20 and FIG. 4B is a cross-sectional view taken along aface including line B-B in FIG. 4A. The element 10 is a rectangularplate-shaped surface acoustic wave element. The length b_(x) of a sideextending in the x direction of the element 10 is 2.0 mm, the lengthb_(y) of a side extending in the y direction is 2.0 mm, the thickness btis 0.35 mm, and the Young's modulus Eb is 230,000 MPa.

The element 10 includes a piezoelectric substrate 11 composed of quartzcrystal, LiTaO₃, LiNbO₃, or the like and a functional part provided onthe piezoelectric substrate 11. The functional part includes two pairsof IDTs 12 made of Al or the like and four input-output electrodes 13made of Ti/Ni/Au. The IDTs 12 and the input-output electrodes 13 areconnected to each other. The coefficient B_(x) of linear expansion of aside extending in the x direction of the element 10 is 16 ppm/° C. andthe coefficient B_(y) of linear expansion of a side extending in the ydirection of the element 10 is 9 ppm/° C. The coefficient of linearexpansion of the side extending in the x direction is different from thecoefficient of linear expansion of the side extending in the ydirection.

A frame-shaped electrode 14 serving as a first frame-shaped electrode isprovided on the surface of the element 10 so as to surround the IDTs 12and the input-output electrodes 13. The frame-shaped electrode 14 has arectangular frame shape and includes strip-shaped portions extending inthe x direction and strip-shaped portions extending in the y direction.The length bl_(x) of the external side of each strip-shaped portionextending in the x direction of the frame-shaped electrode 14 is 2.0 mm,the length bl_(y) of the external side of each strip-shaped portionextending in the y direction is 2.0 mm, the width bw_(x) of thestrip-shaped portion extending in the x direction is 0.18 mm, the widthbw_(y) of the strip-shaped portion extending in the y direction is 0.20mm, and the thickness bet is 0.001 mm.

As shown in FIG. 2A, bumps 15 are fixed on the input-output electrodes13. The bumps 15, which are Au bumps, are formed by a wire bondingprocess. In place of the Au bumps, metal bumps mainly made of Ag, Pd,and Cu solder bumps, or the like may also be used. In place of the wirebonding process, the bumps 15 may be formed by plating, a process ofsetting solder balls, printing, or the like. The height of the bumps 15is preferably higher than the height of the solder sealing frame 4formed on the package substrate 1 and is preferably about 40 μm to about50 μm.

In the package substrate 1 and the element 10, the length of the sidesextending in the x direction and the length of the sides extending inthe y direction are substantially the same. Each of the bondingelectrodes 2 of the package substrate 1 and each of the input-outputelectrodes 13 of the element 10 are disposed at corresponding positions.The frame-shaped electrode 3 of the package substrate 1 and theframe-shaped electrode 14 of the element 10 are also disposed atcorresponding positions.

The frame-shaped electrodes 3 and 14 are made of Ni/Au. Nickel is usedin order to prevent solder corrosion. A metal other than Ni may be usedas long as the metal can prevent solder corrosion. In addition to Ni,examples of such a metal include Pt and Pd. Gold is used in order toensure solderability. A metal other than Au may be used as long as themetal can ensure solderability. In addition to Au, examples of such ametal include Ag, Sn, Pt, and Cu.

A method for bonding the package substrate 1 and the element 10 will nowbe described.

As shown in FIG. 2A, an element 10 including IDTs 12, input-outputelectrodes 13, a frame-shaped electrode 14, and bumps 15 and, as shownin FIG. 2B, a package substrate 1 including bonding electrodes 2, aframe-shaped electrode 3, and a solder sealing frame 4 are prepared.

The package substrate 1 is placed on a support such that the soldersealing frame 4 is disposed on the upper side, and the position of thepackage substrate 1 is fixed. Subsequently, the reverse face of theelement 10 is applied with a vacuum with a bonding tool. The element 10is positioned such that the frame-shaped electrode 3 of the packagesubstrate 1 and the frame-shaped electrode 14 of the element 10correspond below and above. Subsequently, a pressure is applied withultrasonic waves using the bonding tool to bond the bumps 15 with thebonding electrodes 2 of the package substrate 1. Thereby, the bumps 15and the bonding electrodes 2 of the package substrate 1 undergodiffusion bonding. At the same time, the melted solder sealing frame 4is spread on the frame-shaped electrode 14 of the element 10 withwettability to hermetically seal the space between the package substrate1 and the element 10.

Finally, the resulting package substrate 1 and the element 10 are cooledto complete the bonding and sealing. Thus, a hermetically sealedelectronic component device 20 can be produced.

With respect to the electronic component device 20, the differencesQ_(x) and Q_(y) in expansion generated between the package substrate 1and the element 10 will be calculated.

The differences Q_(x) and Q_(y) in expansion in the electronic componentdevice 20 are calculated as follows: The difference Q_(x) in expansionis |7 ppm/° C.−16 ppm/° C.|×2.0 mm=1.8×10⁻⁶ mm/° C., and the differenceQ_(y) in expansion is |7 ppm/° C.−9 ppm/° C.|×2.0 mm=4.0×10⁻⁷ mm/° C.Thus, the difference Q_(x) in expansion is larger than the differenceQ_(y) in expansion.

In the electronic component device 20, the width cw_(x) of thestrip-shaped portion extending in the x direction of the solder sealingframe 4 and widths aw_(x) and bw_(x) of the strip-shaped portionsextending in the x direction of the frame-shaped electrodes 3 and 14,respectively, are 0.18 mm. On the other hand, the width cw_(y) of thestrip-shaped portion extending in the y direction of the solder sealingframe 4 and widths aw_(y) and bw_(y) of the strip-shaped portionsextending in the y direction of the frame-shaped electrodes 3 and 14,respectively, are 0.20 mm. In the electronic component device 20, thedifference Q_(x) in expansion is larger than the difference Q_(y) inexpansion. That is, the widths aw_(x), bw_(x), and cw_(x) of thestrip-shaped portions extending in the x direction of the frame-shapedelectrodes 3 and 14 and the solder sealing frame 4 are smaller than thewidths aw_(y), bw_(y), and cw_(y) of the strip-shaped portions extendingin the y direction.

When the width of the strip-shaped portion extending in the direction inwhich the larger difference in expansion is generated between thedifferences Q_(x) and Q_(y) in expansion is smaller than the width ofthe strip-shaped portion extending in the direction in which the smallerdifference in expansion is generated between the differences Q_(x) andQ_(y) in expansion, the electronic component device 20 can beminiaturized. On the other hand, in the solder sealing frame 4 and theframe-shaped electrodes 3 and 14, the maximum equivalent strainsgenerated in the sides extending in the direction in which the largerdifference in expansion is generated are barely changed. Accordingly,the electronic component device 20 can satisfy the lifetime for thermalshock resistance required for general electronic component devices.

Furthermore, in the electronic component device 20, the thickness ct ofthe solder sealing frame 4 is 0.02 mm (20 μm). By increasing thethickness of the solder sealing frame 4 to about 18 μm or more, when athermal shock is applied during a reliability test or during use, astrain generated at the sealed portion between the package substrate 1and the element 10 can be absorbed by the solder sealing frame 4.Accordingly, in the electronic component device 20, the maximumamplitude of equivalent strain generated in the solder sealing frame 4can be reduced to about 2.2% or less.

In the electronic component device 20, the difference Q_(x) in expansionis larger than the difference Q_(y) in expansion. Accordingly, when thedifference Q_(x) in expansion is about 2.2×10⁻⁵ mm/° C. or less, themaximum amplitude of equivalent strain generated in the solder sealingframe 4 can be reduced to about 2.2% or less. Since the difference Q_(x)in expansion is about 1.8×10⁻⁶ mm/° C., which satisfies the condition ofabout 2.2×10⁻⁵ mm/° C. or less, in the electronic component device 20,the maximum amplitude of equivalent strain generated in the soldersealing frame 4 can be reduced to about 2.2% or less.

With respect to the electronic component device 20, the ratios R_(x) andR_(y) of flexural rigidity in the package substrate 1 and the element 10will be calculated.

The ratios R_(x) and R_(y) of flexural rigidity in the electroniccomponent device 20 are calculated as follows: The ratio R_(x) offlexural rigidity is (0.25³ mm×2.0 mm×340,000 MPa)/(0.35³ mm×2.0mm×230,000 MPa) and the ratio R_(y) of flexural rigidity is (0.25³mm×2.0 mm×340,000 MPa)/(0.35³ mm×2.0 mm×230,000 MPa). The ratio R_(x) offlexural rigidity and the ratio R_(y) of flexural rigidity are the samevalue of about 0.54.

The ratios R_(x) and R_(y) of flexural rigidity in the electroniccomponent device 20 are about 0.54, which satisfies the condition ofabout 1.2 or less. Therefore, in the electronic component device 20, themaximum amplitude of equivalent strain generated in the solder sealingframe 4 can be reduced to about 2.2% or less.

As described above, the maximum amplitude of equivalent strain generatedin the solder sealing frame 4 can be reduced to about 2.2% or less inthe electronic component device 20. Consequently, even when a thermalshock is applied during a reliability test or during use, a strain or afatigue breaking that is generated in the solder sealing frame 4 can besuppressed and thus sealing failure due to breaking of the sealedportion does not occur.

Consequently, the electronic component device 20 has further improvedlifetime for thermal shock resistance and excellent reliability.

In the above preferred embodiment, the solder sealing frame 4 isprovided on the package substrate 1. Alternatively, the solder sealingframe 4 may be provided on the element 10 or may be provided on each ofthe package substrate 1 and the element 10. When the solder sealingframes 4 are provided on both the package substrate 1 and the element10, the solder sealing frames are bonded with each other to performsealing.

With respect to the solder sealing frame 4, the solder sealing frame 4need not be entirely made of a base metal. It is sufficient that atleast the surface thereof is made of a base metal.

In place of metal bumps or solder bumps, base metal bumps such as Albumps may be used as the bumps 15.

A surface acoustic wave element is used as the element 10 in the abovepreferred embodiment. Alternatively, another element such as ahigh-frequency element may also be used as long as the coefficient oflinear expansion in the x direction is different from the coefficient oflinear expansion in the y direction.

A glass epoxy resin is used for the package substrate 1 in the abovepreferred embodiment. Alternatively, another airtight substrate, forexample, a glass substrate, a ceramic substrate made of alumina or thelike, or a crystalline substrate may also be used.

The solder sealing frame 4 may be connected to an earth-side circuitpattern (not shown in the figure) provided on the package substrate 1.

While the present invention has been described with respect to preferredembodiments thereof, it will be apparent to those skilled in the artthat the disclosed invention may be modified in numerous ways and mayassume many preferred embodiments other those specifically set out anddescribed above. Accordingly, it is intended by the appended claims tocover all modifications of the present invention which fall within thetrue spirit and scope of the invention.

1. An electronic component device comprising: a rectangular plate-shapedelement including a functional part and a first frame-shaped electrodesurrounding the functional part, wherein the coefficient of linearexpansion in the x direction along a side of the rectangle is differentfrom the coefficient of linear expansion in the y direction orthogonalto the x direction in the rectangular plane; a substrate including asecond frame-shaped electrode arranged on a front face of the substrateat a position so as to correspond to the first frame-shaped electrode;and a solder sealing frame provided on the surface of at least one ofthe first frame-shaped electrode and the second frame-shaped electrode;wherein each of the first frame-shaped electrode, the secondframe-shaped electrode, and the solder sealing frame includes astrip-shaped portion extending in the x direction and a strip-shapedportion extending in the y direction; the element and the substrate arebonded together with the solder sealing frame, the functional partprovided on the element is hermetically sealed in a space formed betweenthe element and the substrate; and when the difference in expansion inthe x direction between the element and the substrate is represented byQ_(x) and the difference in expansion in the y direction between theelement and the substrate is represented by Q_(y), in each of the firstframe-shaped electrode, the second frame-shaped electrode, and thesolder sealing frame, a width of the strip-shaped portion extending inthe direction having the larger difference in expansion is smaller thana width of the strip-shaped portion extending in the direction havingthe smaller difference in expansion.
 2. The electronic component deviceaccording to claim 1, wherein the thickness of the solder sealing frameis about 18 μm or more.
 3. The electronic component device according toclaim 1, wherein when the coefficient of linear expansion in the xdirection of the substrate is represented by A_(x), the coefficient oflinear expansion in the y direction of the substrate is represented byA_(y), the coefficient of linear expansion in the x direction of theelement is represented by B_(x), the coefficient of linear expansion inthe y direction of the element is represented by B_(y), the length ofthe external side of the strip-shaped portion extending in the xdirection of the first and second frame-shaped electrodes is representedby dl_(x), the length of the external side of the strip-shaped portionextending in the y direction of the first and second frame-shapedelectrodes is represented by dl_(y), the difference Q_(x) in expansionis represented by Q_(x)=|A_(x)−B_(x)|×dl_(x)(mm/°C.), and the differencein expansion is represented by Q_(y)=|A_(y)−B_(y)|×dl_(y)(mm/°C.), thenthe larger difference in expansion is about 2.2×10³¹ ⁵(mm/°C.) or less.4. The electronic component device according to claim 1, wherein whenthe ratio of flexural rigidity in the x direction between the elementand the substrate is represented by R_(x) and the ratio of flexuralrigidity in the y direction between the element and the substrate isrepresented by R_(y), the larger ratio of the flexural rigidity ratiosR_(x) and R_(y) is about 1.2 or less.
 5. The electronic component deviceaccording to claim 1, wherein the element is a surface acoustic waveelement.
 6. The electronic component device according to claim 1,wherein the element is a high frequency element.
 7. An electroniccomponent device comprising: a rectangular plate-shaped elementincluding a functional part and a first frame-shaped electrode, whereinthe coefficient of linear expansion in the x direction along a side ofthe rectangle is different from the coefficient of linear expansion inthe y direction orthogonal to the x direction in the rectangular plane;and a substrate including a second frame-shaped electrode; wherein eachof the first frame-shaped electrode and the second frame-shapedelectrode includes a strip-shaped portion extending in the x directionand a strip-shaped portion extending in the y direction; the element andthe substrate are bonded together with the functional part provided onthe element hermetically sealed in a space formed between the elementand the substrate; and when the difference in expansion in the xdirection between the element and the substrate is represented by Q_(x)and the difference in expansion in the y direction between the elementand the substrate is represented by Q_(y), in each of the firstframe-shaped electrode and the second frame-shaped electrode, a width ofthe strip-shaped portion extending in the direction having the largerdifference in expansion is smaller than a width of the strip-shapedportion extending in the direction having the smaller difference inexpansion.